The invention is adapted to removable disposition on the shank of a conventional putter for use by a golfer in adjusting inadequacy in his vision as between the putter and the hole, which may or may not be targeted by the green pin. It is adaptable to align the putter to the intended line of sight whether or not the putter blade may be open at the toe or closed, relative to the line. In addition the instrument can be used to check "break". For example, if the golfer has to raise the putter heel to make the hole appear level, it is known that the break of the green is to the right of the line of the intended putt. On the other hand, when one has to raise the toe of the putter before the target hole appears level, then it is known that the break is to the left of the intended line of the putt. In use of this instrument, the hole may be viewed at near ground level with the instrument and the ball lined up with the sighting mechanism, immediately preceding striking the ball. In practice the vertical sighting mechanism, which is a part of the overall instrument, is aligned with the soot on the putter where the individual player prefers to strike the ball which may or may not be the "sweet spot" highlighted by the putter manufacturer.
Additionally, the present instrument which is mirror-reflective, preferably at ground level, teaches the player to see the "cut of the grass. Thus, he may accurately ascertain that when the grass is bent toward the ball and away from the hole, the "roll" of his ball will be slower. Conversely, if the cut is observed by reflection to be bent away from the ball and toward the hole, the roll of the ball is going to be faster, etc. Accordingly, the present instrument offers assistance in direction, break and speed of the green. It thus teaches eye-muscle coordination that becomes second nature on the putting green after the instrument has teen detached from the putter. Not only is the device provided with universal quick connect and disconnect means, but also the lightness in weight of the instrument is such as to create no appreciable alteration in the "feel" of the putter. The device is manufactured of durable acrylic polymers requiring minimal care and providing substantial durability. Its primary function is to enhance the eye-muscle coordination which is required to effect accurate putting through the determination of stroke, speed, break, etc.